SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'dc6fd2e51013f2422b8e9de05162f879301810e53784270213ac9bc3c35a8726' 
  AND token = 'eDXLFfakDGKrxk/VVc62C3O+FybQLvml5f0wmmmeEkE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}